The present disclosure is directed to an oral care composition for whitening teeth.
Many individuals are dissatisfied with their current tooth color. Thus, there is a desire for whiter teeth which can be achieved through the use of tooth whitening products. The whitening effect can be produced by chemically altering or removing the stain and/or changing the visual perception of the color of the teeth.
It is known in the literature that the visual perception of a white substance can be altered through the deposition of an optical brightener, blue pigment or blue dye, especially one for which the hue angle (in the CIELAB scale) of the reflected or emitted light is between 200 to 320 degrees. This effect is commonly used in laundry detergent products to make white clothes appear “whiter” to the human eye.
The same concept has been applied to tooth whitening. The natural off-white or yellow color of teeth can be made to appear whiter through the deposition of a blue substance onto teeth. Using pigments with a deposition aid, such as Gantrez® (copolymers of maleic anhydride and with methyl vinylether) or hydroxypropylmethyl cellulose, in toothpaste to make teeth look whiter is disclosed in EP1935395B1.
Dyes are also known in the art for whitening teeth. For example, U.S. Pat. No. 6,030,222 discloses depositing dyes on teeth for whitening when blended with a carrier. US Patent Application Publication 2012/0093905 discloses dyes coupled to certain polymers for whitening teeth. However, dyes have significantly different properties than pigments. In particular, dyes are much more soluble in water than pigments. The solubility of dyes makes them more difficult to deposit and be retained on teeth in a hydrated environment, as described for example, in EP1935395B1.
Additional tooth whitening compositions would be a welcome addition to the art.